Question

Please use C++

Write a recursive function that takes a string parameter and
prints the string in reverse order
changing every lower case letter to upper case and every upper case
letter to lower

Answer 1

To write a recursive function in C++ that reverses a string and changes the case of each letter, define the function to take a string parameter, handle the base case of an empty string, and handle the recursive cases for changing the case of the first character and concatenating it with the result of calling the function recursively on the rest of the string.

Step-by-step explanation:

To write a recursive function in C++ that reverses a string and changes the case of each letter, you can follow these steps:

1. Define the recursive function, let's call it reverseString, that takes a string parameter.
2. If the string is empty, return an empty string.
3. If the first character of the string is a lower case letter, change it to upper case and concatenate it with the result of calling the reverseString function recursively on the rest of the string.
4. If the first character of the string is an upper case letter, change it to lower case and concatenate it with the result of calling the reverseString function recursively on the rest of the string.
5. Return the reversed and case-changed string.

Here's an example implementation:

#include <iostream>
#include <cctype>

std::string reverseString(const std::string& str) {
if(str.empty())
return "";

char firstChar = str[0];
std::string restOfString = str.substr(1);

if(std::islower(firstChar))
firstChar = std::toupper(firstChar);
else if(std::isupper(firstChar))
firstChar = std::tolower(firstChar);

return reverseString(restOfString) + firstChar;
}

int main() {
std::string input;
std::cout << "Enter a string: ";
std::cin >> input;

std::string reversedString = reverseString(input);
std::cout << "Reversed and case-changed string: " << reversedString << std::endl;

return 0;
}